建築物壽命的研究：在台北市的一個實證分析

Life spans of buildings: an empirical study in Taipei city

本研究抽樣蒐集台北市已拆除建物的壽命，以及可能影響壽命久暫的因子，進行統計分析，冀求能找出真正的影響因子。由於抽樣年期固定，且興建年為連續，使得興建年成為解釋建物壽命的共變異變數，本研究於是採用共變異數分析法，來克服此種抽樣所造成的偏差。就木造與磚造建物而言，統計結果顯示構造別與舊建物的容積率為解釋壽命的主要變數。換言之，影響建物壽命的因子有兩類：一為該建物的材質，即其所屬的構造類別；一為經濟因素的考量，此由舊建物的容積率所代表。資料並顯示這兩種構造的壽命分佈有顯著的差異，木造建物的壽命分佈呈現均勻分配，磚造建物的壽命分佈則呈現常態分配。

The aim of this study is to test what factors are statistically significant in explaining the life spans of demolished buildings once existing in Taipei. The covariance analysis is employed to take account of the fact that the data set is drawn from different demolished years. For the data composed of wooden and brick buildings, the statistical analysis shows that the construction type and the floor area ratio of the demolished buildings are the two significant factors. The former one coincides with the traditional belief that the main material used in constructing the buildings will determine their own life spans. The latter one suggests that old buildings with higher floor area ratios, which usually also enjoyed a larger increase in land price, are prone to be demolished earlier. The data also shows that the distributions of life spans for the two types of buildings are quite different. The life span of wooden buildings has a uniform distribution. That of brick buildings, a normal distribution.